As the Obama administration announced plans to step up its military campaign against ISIS this spring, a twenty-eight-year-old army officer, Captain Nathan Michael Smith, took President Barack Obama to court. He argued that the war against ISIS is illegal because Congress has not authorized it. Smith’s action highlights persistent problems with the legal basis for the military campaign, and has generated interest and support from leading legal scholars. And so President Obama, a law professor turned president who pledged to bring in the rule of law to restrain presidents’ use of force, finds himself the target of a lawsuit arguing that his own military initiative is unlawful.

Captain Smith is stationed in Kuwait, as part of the American military effort to defeat ISIS in Iraq and Syria. His claimed injury is that fighting an illegal war requires him to violate his oath to “preserve, protect, and defend the Constitution of the United States.” His lawsuit challenges the fractured logic of the legal basis for the military campaign, including the idea that the Authorization for the Use of Military Force against those who perpetrated the September 11, 2001, terrorist attacks and their supporters somehow extends to an organization that did not exist at the time.

But something more fundamental underlies this dispute. The reason the president has been unable to get Congress to pass a new war authorization isn’t because Congress opposes military action against ISIS, and it isn’t a simple matter of partisan stalemate. It is because there is no real political constituency for military matters. Faraway conflicts upend lives on the battlefield. As long as someone else’s family does the fighting, U.S. military operations have little impact on Americans at home. Most Americans are protected from the costs of armed conflict. There is no required military service since Congress eliminated the draft in 1973. Other changes in the way the country wages war—relying on contractors to reduce the number of troops, and on technologies that make war appear more precise and less destructive—contribute to a buffer between American civilians and the wars their country is fighting. Without voters paying attention, neither the president nor Congress is held accountable.

Election years used to be occasions for pitched battles over whether to go to war. One hundred years ago, for example, as war raged in Europe, and American troops were engaged in skirmishes in Mexico, the question of when and where the United States should use military force was an important election issue.

No one had a larger role in making war an issue in the 1916 election than a former president: Theodore Roosevelt. Not himself a candidate that year, Roosevelt was a forceful surrogate for Republican nominee Charles Evans Hughes. Ever since the British ocean liner Lusitania had been sunk by a German submarine on May 7, 1915, killing over a thousand, including 128 Americans, Roosevelt had excoriated President Woodrow Wilson for failing to respond militarily to defend American rights and honor.

Four days before the election, Roosevelt did his best to bring the Lusitania dead back to life in a harshly partisan address at Cooper Union in New York. Wilson had promised to hold Germany to “strict accountability,” he told his audience, yet Americans continued to die from submarine warfare. “Hundreds of American men, women and children have been murdered on the high seas” and in conflict with Mexico, Roosevelt noted. Yet Wilson had abandoned the dead, had “let them suffer without relief, and without inflicting punishment upon the wrongdoers.” Wilson should be haunted by “the shadows of men, women and children who have risen from the ooze of the ocean bottom and from the graves in foreign lands; the shadows of the helpless whom Mr. Wilson did not dare protect lest he might have to face danger; the shadows of babies gasping pitifully as they sank under the waves.”

Roosevelt’s bitter attack did not place war on the agenda of the campaign, however. The Democratic Party embraced the slogan “He kept us out of war” in support of Wilson. Roosevelt’s flamboyant belligerency enabled Wilson to run against Hughes by running against Roosevelt. The weekend before the election, a full-page ad appeared in leading newspapers that asked: “Wilson and Peace with Honor? Or Hughes with Roosevelt and War?”

The harsh campaign rhetoric was effective in one respect: it signaled to voters that the election would shape American war policy. Hughes, the losing candidate, blamed the outcome on the impact of antiwar campaigning on voters in the West and Midwest. Wilson’s election ultimately would not keep the United States out of the First World War, of course, but it gave the decision to go to war a higher threshold—a threshold that was ultimately met both for Wilson and many Americans after German submarines started sinking American ships without warning in early 1917.

In the aftermath of American engagement in a large-scale war on another continent, pacifists sought to make it more difficult for the country to become embroiled in distant conflicts. They proposed a constitutional amendment to require a public referendum before the country entered another foreign war. In 1935, 75 percent of respondents to a Gallup Poll favored its enactment. It failed in the House of Representatives by only a handful of votes. That was as far as the War Referendum amendment would go, but deep public sentiment against another faraway war led Congress to strengthen neutrality laws.

Building upon the sentiment against military engagement, Franklin Delano Roosevelt, campaigning for reelection in 1936, said: “We are not isolationists except in so far as we seek to isolate ourselves completely from war.” Pressing issues at home mattered most in that election year, but Roosevelt also reassured the public that he would avoid foreign entanglements. FDR would not be a reluctant warrior, like Wilson, however. Instead, as the Second World War broke out, he calibrated American engagement with an eye toward what the political climate would bear.

Americans don’t tend to think of politics as being relevant to U.S. entry into the Second World War, since the United States declared war after the Japanese attack on Pearl Harbor. But the U.S. government chose sides and supported the Allies long before that attack. In September 1940, for example, Roosevelt signed a “destroyers for bases” deal with Great Britain, which transferred destroyers to England in exchange for lengthy leases of British bases. He did not seek congressional approval, but based his actions on an expansive reading of the president’s powers as commander in chief. By late spring of 1940, with Germany occupying Belgium, France, Luxembourg, and the Netherlands, war was firmly on the agenda of that year’s presidential campaign. Republican candidate Wendell Willkie gained traction by claiming that Roosevelt would take the country to war and had a secret plan for this with foreign powers. Roosevelt responded with a pledge he would later regret, telling voters: “Your boys are not going to be sent into any foreign wars.”

During both world wars, supporters of military engagement believed that their president could not send American troops to war without public support. Woodrow Wilson’s Secretary of State, Robert Lansing, who favored U.S. entry into the First World War, wrote in late January 1917:

Sooner or later the die will be cast and we will be at war with Germany. . . . We must nevertheless wait patiently until the Germans do something which will arouse general indignation and make all Americans alive to the peril of German success in this war.

Submarine sinkings resulting in American deaths did the trick.

Something similar was needed to mobilize political support for the Second World War. FDR’s Secretary of War Henry Stimson explained that war with Japan was anticipated, but he thought the public was gripped with “a spirit of isolationism and disbelief in danger.” The administration knew they needed broad public support for war mobilization. For this to happen, “it was desirable . . . that there should remain no doubt in anyone’s mind as to who were the aggressors.” This is why it was better to wait for Japan to fire first.

In both world wars, the political climate constrained formal entry into war, but ultimately, as Theodore Roosevelt had understood, nothing stimulated war support like dead Americans.

American war politics changed in the aftermath of the Second World War, but war had not yet become disconnected from politics. President Harry S. Truman did not ask Congress to declare war before U.S. intervention in Korea in 1950, however. Instead he turned to the new United Nations Security Council. One crucial difference in going to war through a Security Council Resolution was that Truman did not need the kind of catastrophe involving loss of American lives that enabled the declarations of the First and Second World Wars.

American engagement in Vietnam began with a limited number of American “advisors” and little press coverage. President Lyndon Baines Johnson brought that war into American electoral politics in 1964. He carefully positioned himself as less belligerent than Republican nominee Senator Barry Goldwater of Arizona. But in contrast to Wilson and FDR who had avoided calling for military engagement before presidential elections, Johnson successfully pressed to get an authorization for the use of force in Vietnam passed before the Democratic National Convention. A draft authorization for war had been drawn up in the spring, but the president initially held off on asking Congress to pass it. He waited for an event that would galvanize popular support.

When the U.S. destroyer Maddox, on patrol in the Gulf of Tonkin, reported that it was under attack for a second time on August 4, 1964, Johnson had the incident he had been waiting for. He used the episode to get his military authorization passed, emphasizing to congressional leaders the need for a swift and strong American response. In the meantime, however, confusion surfaced about the attack, and the captain of the Maddox cabled Washington to advise that action should not be taken until the situation was evaluated. Years later, declassified documents demonstrated that the second attack never happened.

The language of the Gulf of Tonkin Resolution was breathtakingly broad. It did not identify an enemy or a precise geographic area, placing the judgment for war in the hands of the president. Senator Gaylord Nelson of Wisconsin sought to amend the resolution to clarify that it would not authorize sending American ground troops to Vietnam. Senator William Fulbright of Arkansas pressed him to drop it. An amendment would send the resolution back to the House of Representatives, so that it would not be passed before the convention. The Republicans had just nominated Goldwater, a hawk. Johnson wanted the resolution in order to look strong on defense. He would go on to be elected by a landslide in November. Four months later, 3,500 Marines, the first American ground troops, landed at Da Nang Air Base in Vietnam.

President Johnson was ultimately undone by Vietnam. In 1968, over 500,000 American troops, many of them draftees, were serving in the war, and over 16,500 troops were killed in that year alone. Facing widespread antiwar protest and deep divisions in the country and in his own party, LBJ announced that he would not seek reelection. It was the last time a popular movement against war shaped the outcome of a presidential election.

Although Vietnam weakened Johnson, he left behind the legacy of a shift in the political calculus. In later elections, a candidate’s willingness to use force was now most often a positive trait, not a negative one. It seemed to show that they had the resolve to be Commander in Chief.

Johnson’s successor, Richard M. Nixon, made ending the military draft a campaign promise, fueled by the argument that the draft violated free-market principles. This had a lasting political impact. The absence of a draft took away the broader vulnerability of most Americans to their country’s use of force, severing the tie between most American families and the ultimate cost of the country’s entry into war.

Over time, serving in the military became concentrated in particular families and communities. By 2010 a smaller proportion of Americans served in the Armed Forces than at any time since before the buildup for the Second World War. As post–9/11 conflicts drag on, the impact of war has been palpable in communities around American military bases. Elsewhere in the United States, civilian life is largely unaffected. For most American civilians, war is not a personal experience. War is a story in the newspaper that can be read or ignored.

Getting rid of the draft was tremendously important to the atrophy of political engagement with American war. Because of that, restoring the draft is often seen as a corrective to the contemporary military/civilian divide. But the problem is more intractable because it is multi-causal. The relationship between the American public and war continued to change after Vietnam. Ending the draft was just the first of three important changes in the way the country goes to war that would distance the American people from the carnage wrought by their nation’s use of force.

The second development was the increased privatization of the armed services. Reliance on private military contractors grew in the 1990s in the context of a broader move to outsource government tasks to private industry. Use of contractors has expanded in the post–9/11 years. Once greatly outnumbered by troops, contractors have outnumbered U.S. military personnel in Afghanistan, and about equaled them in Iraq, according to U.S. government statistics. Relying on contractors for many of the tasks traditionally performed by military personnel has enabled the United States to project more force with fewer soldiers on the line. There are also fewer military casualties, and contractor injuries and deaths are not added to military casualty statistics. The full human cost of war is dispersed and hard to track.

The third change in the way the country goes to war was technological. During Operation Desert Shield in the Persian Gulf (1990–91), the United States used new guided missiles and “smart bombs” designed to hit a precise target. In media coverage of the war, the image of a computer screen showing a bomb hitting a target made war seem clean and precise. Relying on airpower and precision-guided weapons was a conscious strategy by U.S. military leaders to minimize American casualties and “collateral damage,” otherwise known as injured and dead civilians. Reducing casualties is of course laudatory, but a key reason was to keep U.S. and civilian casualties from undermining the American public’s support for the conflict.

High-tech war has been a particular focus in the Bush and Obama administrations, with the use of drones for targeted killing. This allows the United States to project deadly force without American personnel physically present. Now, the shooter can be a continent away from the target. And media coverage is exceedingly difficult in this kind of warfare. There are no embedded reporters at the site of a drone strike, and access is limited for media who might otherwise verify or question government reporting.

Over time, this trilogy—no military draft, reliance on contractors, and high-tech warfare—has insulated the American public from the cost and the consequences of war. Without a personal stake, Americans pay little attention to their country’s ongoing wars. Presidents no longer need to wait for an attack on Americans to galvanize public support for armed conflict. There is simply no need to mobilize the citizenry.

This helps to explain the circumstances that led to Captain Smith’s lawsuit. President Obama has been relying on strained interpretations of preexisting Authorizations for the Use of Military Force, and his own presidential power as commander in chief, for authority to conduct ongoing military action in the Middle East. He asked Congress to pass a new authorization for war against ISIS. Congress appears to support this military campaign, but has not exercised its power to authorize it. The lack of an authorization does not limit Obama’s deployment of military force, however. Instead it provides a justification for the expansion of the president’s power to act on his own.

There has been much attention given to the way government secrecy about the use of force and surveillance under the Bush and Obama administrations enables unchecked presidential power. But an important cause of the absence of accountability is deep in the structure of American war politics. The direct exposure of most Americans to this war is limited to news sources and social media, when they choose to pay attention at all. With little personal stake, they make no demands of their elected officials. The inattention of voters means that members of Congress have few incentives to prioritize it. Without Congressional action, war power devolves to the president. This has resulted in ongoing war with no end in sight.

The fracturing of American war politics has been many years in the making, and there is no easy fix. Smith’s lawsuit is unlikely to get Congress to act, and most certainly won’t result in troop withdrawals. When it comes to limiting presidential power, there has simply never been a substitute for political movements against war.

Mary L. Dudziak is a professor of Law at Emory University and the author of War Time: An Idea, Its History, Its Consequences (Oxford University Press, 2013).